When testing a new solid rocket motor design it is desirable to know distribution and rates of burning within different regions of the fuel, so that the fuel can be best shaped to obtain a full burn.
Monitoring of internal rocket motor conditions during a test burn has been a difficult problem. Probes which penetrate the pressure vessel can cause vessel failure. Furthermore, most probes cannot withstand the high temperature conditions within the burning rocket.
Capacitance and magnetic gages have been used for many years with conducting gases in shock-tube laboratory technology. This invention is an extension of laboratory techniques to the interior of a burning rocket.